package com.hailintang.demo.leetcode;

import java.util.LinkedList;

/**
 * @author hailin.tang
 * @date 2020/5/28 8:35 下午
 * @function
 */
public class Chinese_394 {
    public static void main(String[] args) {
        String s = "3[a]2[bc]";
        String s1 = decodeString(s);
        System.out.println(s1);
    }

    public static String decodeString(String s) {
        StringBuilder res = new StringBuilder();
        int multi = 0;
        LinkedList<Integer> stack_multi = new LinkedList<>();
        LinkedList<String> stack_res = new LinkedList<>();
        for (Character c : s.toCharArray()) {
            if (c == '[') {
                stack_multi.addLast(multi);
                stack_res.addLast(res.toString());
                multi = 0;
                res = new StringBuilder();
            } else if (c == ']') {
                StringBuilder tmp = new StringBuilder();
                int cur_multi = stack_multi.removeLast();
                for (int i = 0; i < cur_multi; i++) tmp.append(res);
                res = new StringBuilder(stack_res.removeLast() + tmp);
            } else if (c >= '0' && c <= '9') multi = multi * 10 + Integer.parseInt(c + "");
            else res.append(c);
        }
        return res.toString();
    }
}
